1. Field of the Invention
Flexible and inflexible non-breakable thermometers are applicable to a wide variety of uses. The digital thermometer which allows for rapid reading of the temperature of its environment can be used in environments where it would be subject to abuse, without fear of contamination of the environment by mercury or the presence of glass fragments. In addition, there are many situations where a thermometer is desirable which is compact, easily mounted, safe or ornamental.
Compositions are available which respond to a particular temperature by undergoing a color change. The availability of these compositions allows for flexibility in fabricating temperature sensing devices.
2. Description of the Prior Art
U.S. patents of interest include U.S. Pat. Nos. 3,440,882; 3,585,381; 3,617,374; 3,619,254; 3,633,425; 3,667,039; 3,697,297; and 3,704,625. Also of interest is the British analog of U.S. Pat. No. 3,697,297, British Pat. No. 1,138,590. Temperature responsive liquid crystals are commercially available from Liquid Crystal Industries, Turtle Creek, Pennsylvania and Hoffman-LaRoche, Nutley, N.J.